Precision Zone specializes in Yaskawa product repairs servicing a wide range of AC Servo series such as Yaskawa USAREM Series Motors.

The USAREM series achieves high accuracy, quick response control under any environmental condition, and smooth, powerful operation even at low-speed range. This is one of Yaskawa’s smaller A/C servo series of servo motors. Several different series of drives utilized the USAREM motor in its motion control system including factory automation and a wide range of CNC machines. This motor series is what started Yaskawa’s legacy in motion controls.

When assessing the functionality of a motor, our engineering team typically conducts a six-step check:

Visual Overview Check

Static Test

Back EMF

Feedback Check

Alarm Code Troubleshooting

Disassembly and Cleaning

This overview is Precision Zone’s basic troubleshooting process. Once our repair team starts on the job we use specialized, customized test fixtures, SKF Baker AVAIV-4, Huntron tracker, signal generator, oscilloscope, milli and mega ohm meters and other necessary tools to assure quality repair. Most importantly, every repair is fully tested in custom-built simulators under load to replicate real-life working environment.

REPAIR EVALUATION PROCESS FOR USAREM SERVO MOTORS

Visual Overview Check

When conducting a visual check, the technician inspects the motor for any mechanical damage to the power connecter, junction box, rotor shaft, oil seals and encoder covers.
During the visual inspection the technician notes excessive dirt, oil or grease on cooling fans and all other parts of the motor.

Static Test Basic

Precision Zone repair technicians use an SKF Baker Advanced Winding Analyzer to fully evaluate the stator winding. The SKF Baker performs a wide range of electrical tests, including surge, DC hipot, meg-Ohm and winding resistance tests. In the instance of winding resistance each phase is tested with each other; and the mega ohm readings should be no less than 300 mega ohms.

Winding Resistance Testing

Multimeter Positive Lead

U

Multimeter Negative Lead

V

Resistance Check

Approximately 0.85-23.0 Ohm’s

Multimeter Positive Lead

U

Multimeter Negative Lead

W

Resistance Check

Approximately 0.85-23.0 Ohm’s

Multimeter Positive Lead

V

Multimeter Negative Lead

W

Resistance Check

Approximately 0.85-23.0 Ohm’s

Reading should be balanced across all three phases.

Mega Ohm Testing

Mega Ohm Meter Negative Lead

Ground

Mega Ohm Meter Positive Lead

U V W

Insulation Check

Must be above 300 Mega Ohms

Back EMF Check

If a servo motor passes the static checks it will be back driven and have the back EMF checked. With our in house magnetizing service we can bring back to life servo motors with weak magnets.

Feedback Check

Repair technicians can test encoders in a number of different ways. Our Mitchell Electrics TI-5000EX system can be used to read, write and record encoder count and data information. We have Mitchell Electrics TI-5250 systems that can be used to see live encoder pulses on an oscilloscope. Connecting encoders directly to the manufacture’s drive is another way we can verify if an encoder is working correctly.

Alarm Codes Troubleshooting

Alarms that the CACR-IR/HR/SR Servopack will display when the USAREM Series Motors have a problem are the following. These codes displayed are :

Alarm Code

Code Type

1

Overcurrent

5

Overspeed

0

Absolute Error

8

Position Error

C

PG Disconnection

J

Overflow

L

Overrun

Disassembly and Cleaning

All motors are fully dissembled washed and baked. Rotors are checked for bent shafts and bearing journal common problems. The stator winding is rechecked after the baking process. Holding brakes are refurbished and the holding torque is checked. Both the drive end and opposite drive end housing bearing surfaces are checked. Once the evaluation is completed a computer report is generated with all the findings.

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